Railway traffic controlling apparatus



0d. 10, 1933. R R KEMMERER 1,930,171

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Sept. 6, 1930 3 Sheets-Sheet l V V --West F 1 INVENTOR;

My ATTORNEY OCt. 10, 1933. R R KEMMERER RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Sept. 6, 1930 3 Sheets-Sheet 2 F INVENTORi 1 ATTORNEY Oct. 10, 1933. R M R 1,930,171

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Sept. 6, 1930 3 Sheets-Sheet 3 X X EQSLQ P F 1 INVENTOR R-ali'Kernmerah QR-W FA ATTORNEY Patented Oct. 10, 1933 UNITED I STATES RAILWAY TRAFFIC CONTROLLING APPARATUS Ralph It. Kemmerer, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application September 6, 1930. Serial No. 480,161

Renewed April 16, 1932 36 Claims. (01. 246-33) My invention relates to railway traffic controlling apparatus for utilizing coded current in track circuits for the control of signals which may be either wayside signals or train carried signals or both, and more particularly it relates to apparatus for utilizing coded current in the running rails and/ or line circuits for establishing directional control on a single track railway.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying Figs. 1 1 and 1, when placed end to' end in the order named, with Fig. 1 on the left, form a diagrammatic view showing one form of apparatus embodying my invention.

In the accompanying drawings, like characters of reference designate corresponding parts, an exponent being added to the reference character to distinguish the location of the part.

In the description, I shall assume the left-hand end of the figures 'to be west and the right-hand end to be east, and I shall speak of a train traveling from the right to the left as a westbound train, and one traveling from the left to the right as an eastbound train.

The reference characters 1 and 2 designate the track rails of a stretch of single track railway extending between two passing sidings P and P These rails are divided by customary insulated rail joints 3 into the track sections V-W, WX, etc., and while in the drawings, the stretch of track between the two sidings is shown arranged with only two intermediate track sections, it will be understood that any number of such track sections may be employed.

The energy for the operation of the apparatus is furnished by line transformers G, one of which is located at each junction of adjacent track sections. The primary 7 of each of these transformers is connected to a transmission line E, which is constantly supplied with alternating current of a convenient commercial frequency such as cycles per second from a source which is not shown in the drawings.

An auxiliary transformer M is located at each junction of adjacent track sections, and its primary 8 is connected to the secondary 9 of the associated transformer G. The secondary 10 of each transformer M is connected to 'the input terminals of a rectifier 11 whichfurnishes direct current for the operation of certain parts of the apparatus of my invention.

Each track section is provided with a twoelement track relay TR which has a track wind- .transformer T, the secondary 19 of which is coning 12 connected across the rails atone end of the track section and a second winding 13 con stantly supplied with alternating current from the secondary 9 of the associated transformer G.

The track winding 12 of each track relay TR is 60 connected in series with a secondary winding 14 of an associated impedance transformer T1, and connected directly across the track rails is'the secondary winding 15' of a code feeding transformer T2 in series with a current limiting re- ,gresses.

A master line relay MR is located at the junction of adjacent track sections, and each line relay MRis supplied with coded energy over a pair of line wires 17 and 18 in accordance with certain traffic conditions as will be hereinafter pointed out.

.Each track section is'provided witha track nected through the usual current limiting reactance 20 across the rails of the section at the end opposite from the track relay The primary 21 of each track transformer T is supplied with alternating current from an associated transformer G which current is periodically interrupted or coded at the rate of 40, 80 or 180 cycles per minute or any other code frequency desired, and it follows that when any given track section is unoccupied, the track relay of that'section is operated at the rate of 40, 80 or 180 cycles per minute, except under certain specific conditions to be. pointed out later.

Each track section is' provided with a code transmitter CT. including a motor element 22 (see Fig. l constantly supplied with direct current by the rectifier 11 of the same location. 'This code transmitter isto be of any of the standard types commonly used for this kind' of work and, as the specific structure of the code transmitter or the manner whereby it actuates contacts at different speedsform no part of my invention in this specification, it will be under-' stood that both upper contacts 23 and 24 periodically close their respective front'and back contacts at a rate of 180 times per minute,'that both code of 180 cycles per minute.

center contacts 25 and 26 close their respective front and back contacts at a rate of 80 times per minute, and that both the lower contacts 2''! and 28 close their respective front contacts at a rate of 40 times per minute.

Each track relay controls decoding-apparatus involving three relays TP, 2H and 2D in such a manner that these relays are selectively responof the rectifier 11 (see Fig; l alongpositive wire B, front contact of armature 31 of the relay TR", the right-hand half of the primary winding 30 of the transformer ZDT center tap, and wire C to the lower or negative terminal of ,the rectifier 11. When the relay TR is deenergized, current flows through the back contact of the armature 31 to the left-hand half of the primary 30 and back to the negative terminal of rectifier 11. It follows then, that with the track relay operated by a coded current, an

.alternatingvoltageis induced in the secondary 35 of the decoding transformer 2DT,flthe"fre quency of which is the same as the frequency of operation of the track relay, while with the track relay either continuously energized or continuously deenergized no voltage is induced in the secondary of the decoding transformer. A condenser 36 may be connected across the primary 30 of transformer 2DT to reduce thesparking at the contacts of thearmature 31 of relay Each transformer 2DT'is provided with a firstsecondary circuit (see Fig; 1 which includes a reactor 3'7 and a rectifier 38 in series. The output terminals of this rectifier 38 are con- ,nected ,with decoding relay 1?". The parts of .this circuit are so proportioned and adjusted that relay. TP will respond to any one of the three codes but most eiiiciently tothe 40 code.

.TranSfornierZDT is provided with 'asecond secondary circuit'which includes a reactor 39 in series with three condensers 41, 4 2 and 43 in multiple, while-a rectifier 44 is connected in shunt with a partof the reactor 39. A decoding relay 2H is connectedto the output terminals ,of the rectifier 44, andthe partsof this circuit are so proportioned that the relay 2H responds only to the code of 80 cycles per minute. A third secondary circuit is connected to the secondary '35 of the transformer 2DT including a reactor v 45 and a condenser ,46 in series; .A rectifier 4'? has its input 'terminalsconnected. across a portion-of the reactor 45 and the output terminals of the rectifier are connected with the decoding relay 2D. The parts of this'circuitares'o proportioned that the relay 2D responds only to the A slow-acting repeater relay, designated by. thereference characterfl2P together with a thermal unit TU, whose function/1's to retardthe pickup of the reIayZP are associated with" thedelcoding relays. 2H? and.2P by acircuit consisting of posi- .;tive terminal of the rectifier 11, positive wire 13,

wire 48, front contact 49 of relay 2Dl, wire 50,

from contact 53, coil of relay 2P wire 54, and negative wire C. to the negative, terminal of the rectifier ll, or in place of the front contact 49, this circuit may branch fromwire 48, through the front contact 5'1 of the relay 2HV, to the wire 50, and then as before traced. It will be noted that this is a stick circuit which requires that the associated thermal unit TU, which is connected in circuit when the relay 2P is deenergized closing its back contact 55, must first be heated. The circuit for heating the element 56 of the thermal unit TU extends from the positive terminal of. rectifier 11, wire B, wire 48, either front contact 49 of relay 2D or front contact 57 of relay 2H", wire 50, back contact 55, heating element .56, and wires 54 and C to the negative terminal of rectifier 11. As soon as the heating element 56 heats up so as to close its contact 58, a pick up circuit is established through the contact 58 to the relay ZP that is the same as traced for the heating element 56 up to wire thence by contact 58, winding of relay 2P and wires 54 and C to the negative terminal of rectifier 11. With relay 2P once up, it closes the stick circuit above traced, and opens the circuit to the heating element 56 at the back contact 55.

Each master line relay MR controls a decoding apparatus including the decoding relays MP,

1D, 1H, a decoding transformer lDT, and a slowacting repeater relay 1P with an associated thermal unit in exactly the same manner as described for the decoding transformer, relays, etc., associated with the trackrelay TR. Thus it is considered sufficient to say that relay MP responds to any of the codes 40, 80, and 180 but most eiiiciently to the 40 code, that the relay lHresponds only to the code and that the relay 1D responds only to the 180 code.

At the junction of adjacent track sections.

there are provided directional stick relays indicated by the reference characters is and 23 with an appropriate exponent. These stick relays perform functions similar to thoseof the directional stick relays used in standard absolute permissive block signal systems, that is, to

establish directional control and permit following train movements. As the manner of selecting the directional relay is the same at each location, only one location will be described and I shall use Fig, 1 directional relay lS associated with westbound tramc extends from the positive terminal of the rectifier 11, along positive wire B, wire 59. back contact'60 of relay 2P wire fil, back contact 62 of The pick-up circuit for the directional relay 2S wire 63, back contact 64 of relayMP wire 65, front contact 66 of relay IP wire 67, relay IS, and wires 68 and C to the negative terminal of rectifier 11. The stick circuitfor this directional relay 13 extends from wire 65, along wire 70, front contact 69 of the relay 18 to wire 67. The directional relay 'ZS associated with eastbound trafiic is provided with a similar pick-up circuit that extends from the positive terminal of rectifier 11, along wire B, wire 71, back contact 72 0f relay IP wire 73, back contact 74 of directional relay lS wire '75, back contact '76 of relay TP wire 77, front contact 78 of relay ZP wire 79, coil of relay 2S, and wires 86 and'C to the negative terminal of rectifier 11.. The stick circuit for relay 28 branches from wire 77, along wire 8l,'iront contact 82 of the relay 25 to the wire 79.

Each section is provided with a wayside signal located at each end of the section and these signals governtrafiic in opposite directions through i the section. Signals governing eastbound traffic are designated by the reference character R, with an exponent corresponding to the location, while the signals governing westbound traffic are desig nated by the reference character L with an exponent. corresponding to the location. These ing to the code current energizing the relay TR,

wayside signals may be any of the standard types and are here shown as three-position light signals. The lighting circuits of each signal are controlled by the decoding relays for the corresponding section, and as the light circuits of all signals are alike, a description of any one will be sufiicient for the understanding of all. Referring to signal RW the proceed light circuit is from one terminal of secondary 9 of transformer G along wire BXllO, wire 83, front contact 84 f relay wire 85, front contact 86 of relay ZP wire 87, back contact 88 of relay 2H wire front contact 90, Wire 91, proceed light and wires 92 and CXllO, to the opposite terminal of secondary 9. The caution light circuit for signal RW is the same as that just traced for the proceed circuit up to wire 87, then front contact 93 of relay 2H wire 94, caution light Y, and wires 92 and CXllO to secondary 9. The stop light circuit for the signal RW may be energized by a circuit branching from wire 83, back contact 95 of relay TP wire 96, stop light R, and wires 92 and CXllO t the secondary 9, or it may be energized by a circuit branching from wire 85, back contact 97 of relay 239 to the wire 96, and as before, or once again it may be energized by a circuit branching from wire 89 by back contact 98 of .relay 2D to the wire. and as before traced.

Having pointed out the various devices with which each track section of my invention is provided, I shall now describe its operation, and I shall first assume that all track sections between the two sidings are unoccupied. Normally coded, alternating current is supplied to the track rails of each track section by the transformer T of the section inasmuch as the primary winding 21 of transformer T has one side connected by the common wire CXllO' to one terminal of the secondary 9 of the transformer G, and its other terminal is connected to the opposite side of the secondary 9 over front contact 100 of the MP relay at that location, wire 101, front contact 102 of the 2P relay, wire 103, 180 code contact 24 of the code transmitter CT, and thence by wire Exile to secondary 9. It follows thenthat each track relay TR will normally follow each 180 code cycle alternately closing the frontand back contact of its armature 31.

is connected to the heel of the armature 31 by the positive wire B and also that the extreme ends of the primary winding of the decoding, transformer 233T are connected to the front and'back contacts, respectively, and that the center tap of the primary winding is connected to the negative terminal of rectifier 11 by the negative wire C. It follows then that with the front andback contacts of track relay TR alternately closed the half of the primary winding of the decoding transformer fed by the front contact will be energized for the duration of the on code'period, thereby building up flux in one direction and, when the on? period of the code cycle occurs, the back contact closes and the other half of the primary winding 30 will be energized, but in the reverse diaction from the first. This will cause the flux to build up in the first instance and to die down and build up'in the opposite direction with each 180 code cycle. Withthe building up of a flux in one direction and the dying'down and build ing up in the opposite direction, a voltage is induced in the secondary winding of the decoding transformer wlth a frequency correspond- It has been already noted that the positive terminal of rectifier 11,

and, as just pointed out, under normal conditions this is the 180 code. As described earlier in the description, the secondary circuit feeding rectifier 47 is tuned to resonance at that frequency and, therefore, the 2D relay of each track section is normally energized. It also follows that the circuit for the decoding relay TP of each section being untuned and responsive to all codes will cause the TP relay to be normally energized. A resistance 105 may be placed in series with the coil of the relay TP when it is deenergized for the purpose of quickening the pick-up and byenergize the relay 2P, and these relays select the circuit to supply 180 code energy to the next section to the left and to govern the operation of wayside signals.

I desire to here point out that if the coded energy supplied to therails of a track section be of the 80 code at which frequency the circuit for the relay 2H is tuned to resonancethe relay 2D at that location will drop and the relay 2H will be energized and the relays'TP and 2P are each retained energized. It follows, therefore, that with the rails of a given track section supplied with current of the 80 code the circuit to supply 180 code current to the rails of the track section to the'left is closed.

With current of 40 code supplied to the rails of a track section, the relay TP of that section is retained energized but both the 2H and 2D relays of the section are deenergized and, in turn, the

associated repeater relay 2P is deenergized.

This results in the closing of the 80 code circuitm if the directional relay 2S is up, to the track section to the left, or in closing the 40 code circuit inthe event the directional relay 253 is down. Referring to Fig. 1 the circuit to supply the so code current is from the secondary 9 of transformer G", wire BXllO, 80 code contact 26, wire .99, front contact 108 of directional relay 29, wire 148, back contact 147 of relay 2P wire 101, front contact 100, primary 2i, and the wire CXi in to secondary 9. The circuit to supply the 40 cod; isfrom the secondary 9 by Wire BX110, 4O code contact 28, wire 159, back contact 149, and then as traced for the 80 code circuit.

With each successive track section normally supplied with coded energy in the manner similar to that just described, it becomes apparent that this coded track current affords a means of controlling wayside signals governing trafiic in one direction, and also to control train carried apparatus receiving current inductively from the "track rails such, for example, as the apparatus disclosed and claimed in an application for Letters. Patent of the. United States, filed by P. N..

of alternating current and then applying such to a pair of line wires, givesa means of operating as many relays as required to control the application of train governing current to the rails and to control wayside signals for governing traffic 'in the opposite direction from that permitted by the current normally fed to the rails by track transformers. I will now describe the operation of such line circuits. Y The master relay MR, as in the case of track relay TR, is a two-element relay. One element 112 continuously supplied with alternating current by the wires BXllO and CXllO from the secondary 9 of the associated transformer G as will be apparent from the drawings. The second element 117 of the MR relay is supplied with coded current from the next block to the left over the line wires 17 and 18. Taking the case of relay MR", the normal circuit for supplying the 180 code current extends from one side of secondary 9 of transformer G" along wire BXllO, 180 code contact 24 of code transmitter CT", wires 103 and 113, front contact 114 of the relay 1?", wire 115, front contact 116 of relay TP", wire 18, element 117 of relay MR Wire 17, and wire CXllO to the opposite terminal of secondary 9. Under certain traflic conditions, as will be pointed out later, the relay MR is supplied with either 80 code or 40 code current. The circuit to supply 80 code energy to the element 117 'of relay MR may take either of two paths, the first being from the secondary 9 of the transformer G", through 80 code contact 25 of code transmitter CT", wire 119, back contact 129 of MP", wire 121, back contact 122 of relay 1?", and then as before traced'for the 180 code current. The second path extends from secondary 9 through 80 code contact 25 of CT", along wire 126, front contact 127 of relay M1 wire 121, and as before traced. The circuit to supply the element 117 of relay MR with 40 code current is from secondary 9 of G" through 40 code contact 28 of CT", a front contact 123 of directional relay 2S", back contact 124 of relay TP" and then as before traced for'180 codecurrent. It is to be noted that at intermediate signal locations, 49 code current is supplied to the master line relay to the right when the MP relay at the intermediate location is up andthe 1P relay is down, instead of 88 code current as just described at the leaving location V. Looking at Fig. 1 40 code current is supplied to the master line relay MR through the 40 code contact 27 of code transmitter CT" by a circuit which includes front contact 109 of relay MP back contact '155 of relay 1P and front contact 151 of relay TP The explanation of the decoding apparatus given for the decoding relays TP, and 2D is identically the same for the decoding relays 1D, 1H and and the function of the repeater relay 1P is similar to that described for the repeater relay 2P. These decoding relaysassociated with the master line relay control wayside signals governing traflic in a direction opposite to the signals controlledby the decoding relays associated with the track relay TR. These decoding relays associated with line relay MR also control the application of train governing current to the track rails, at the track relay end of each track section when that end becomes an exit end, by means of the code feeding trans-' former T2, as will be shortly pointed out.

I will now describe the operation of the apparatus for a train moving from the leftto the right, that is, an eastbound train, and I shall assume that this train has entered the track section to the left of the signal R". The relay MR." will receive no code due to the track relay w V-W past signal R" in a clear position, the first 'being down. Because of the absence of 180, 80

or 40 code, the relays 1D", MP" and 111" will be deenergized, deenergizing, in turn, the relay 1?". With the deenergizing of the'lD", MP" and 1H" relays, at the leaving signal of the passing siding P1, the MR relay at the first intermediate signal location, that is, relay MR is caused to operate on 80 code current by the circuit previously traced, and which includes the back contact 120 of relay MP" and back contact 122 of the 1P" relay. 1 The MR"" relay being thus operated on code, a caution signal is displayed by signal With the train advancing into the block pair of wheels shunt the track relay TR" and relays TP", 2H", 2D" and 2P" all become deenergized. The deenergizing of relay TP" opens the contact 116 and thus shuts off the 8!) code to the relay MR However, relay 2?" being slowreleasing will not open its front contacts until sometime after relay TP" has closed its back contacts, and thus effect the energization of the directional stick relay 25", the pick-up circuit for relay 25;" being similar to that previously described for the directional relay 255". With the energizing of the relay 28", the line relay MR" is supplied with H) code energy from the secondary 9 of transformer G", through the code contact 28 of CT" by the circuit previously traced and which includes the front contact 123 of directional relay 28". With the relay MR" thus operating on 40 code, its associated relays ID", 131"", and lP are all down, and it follows, therefore, that each successive MR relay to the next passing siding is caused to operate on 40 code current, and this will cause all the westbound signals to assume the stop position. With the deenergizing of the TP" relay and the energizing of the directional relay 2S", it will be noted that it is necessary for the directional relay 2S" to pick up and to stick up in order to maintain train governing current on the track in advance of a train by the track transformer 'T 1 It will also be noted that with relay 23" up,

code energy is supplied to the track of the section to the left of the track section V-W, the circuitincluding the back contact 107 of relay 2P". It follows that a caution indication will be displayed by the next signal in the rear of signal R", the signal R" having assumed a stop pedance transformer T1" has its primary wind 1.

ing 128 short-circuited through back contact 129 of relay TP", back contact 130 of relay 1?", and a front contact 101 of relay MP", and this short-circuiting results in the secondary winding 14 offering small impedance to the coder energy thereby permitting the relay TR" to readily respond to the 80 code impulses applied to the relay as the train leaves the section V-W. -With the relay TR" operated by 80 code energy,

the relays TP" and 2H" will pick up and then, in turn, relay 2P". With relay 2H" picking up, the directional relay 28" is deenergized, and with relay 2P" up, the-track transformer T" will be supplied with 180 code through the front contact 1020f 2P" and the front contact 100 of MP with theresult that the signal to the left of R will be cleared in a manner previously described under normal conditions, With the deenergizing of directional relay 28", direct 'current is supplied from the rectifier 11 to the thermal unit associated with relay lP by a circuit including wire B, wire 132, front contact In summing up the operation for an eastbound.

train, We find that all opposing westbound signals are set at stop to the next passingsiding, that coded energy is supplied to the track rails at the exit end of each track section by means of the track transformer T, that this coded energy is varied in accordance with the number of unoccupied track sections in advance of the train, and that this coded current controls wayside signals to govern the train andv is also adapted to control train carried cab signals, and that the directional relays assure that proper code energy is supplied to the rails of the track section to the rear of the trainto permit following train movements and also to. provide the clearing of. the opposing wayside signals behind the train.

I shall describe next the operation of a westbound train and, as before, I shall assume that all track sections between the sidings are unoccupied and that the train occupies the track section to the right of section W-X. By the train occupying section WX, it shunts the track relay TE and concurrently relays TP 2H and'2D are deenergized, and, in turn, the repeater relay 2P is deenergized. This resultsin' 'code energy being applied to the track circuit of section W-X as follows: Secondary 9 of transformer G wire BXllO, 80 code contact 26 of code transmitter CT wire 250, back contact 51, front contact of relay MP primary 21, and wire CX to secondary 9. It follows then that as the train occupies the section to the right of W-X, that the eastbound signal R is at stop and the first intermediate signal R is at caution.

As the train'advances into section WX an shunts the track relay TR the relay TP now becomes deenergized and with relay TP deenergized. code energy is supplied to rails of the section W-X at the exit end by means of the code feeding transformer T2 in the following manner. One side of the primary 235 is connected to one terminal of secondary 9 of transformer G by the wire CX110 and the other side of primary 235 is connected to the other terminal of sec! ondary 9 over-wire 236, back contact 237, wire 238, front contact 239, wire 240, 180 code contact 23 of code transmitter CTW and-wire BXllO. It will bevnoted that wire 236 is also connected. to one side of the primary 141 of the impedance transformer Tl and that the other side of the primary 141 is connected to a back contact 142 of code transmitter CT by wire 143. Thus we havecode energy fed to the rails when the front contact of the code contact 23. is closed and during the interval when the backcontact 142 is closed no code is beingfed tothe' rails and the, primary 141 of T1?" is short-circuited. This short-circuiting of the primary of the impedance trans? former T1 is to permit relay TR to pick up with the first impulse of energy supplied to the relay by the track transformer T when the train leavesthe section. Furthermore, the train governing codeenergy fed to the rails by the code feeding transformer T2 is in the reverse direction from vthat supplied by :the normal track transformer T and it follows that what small energy reaches the element 12 of track relay TR through, the impedance transformer .Tl

is in a direction to hold the relay TR down.

This- 180 codeenergy applied to the rails" of the track section W -X by the code feeding transformer T2 controls the train carried cab signal.

Withthe deenergizing of relay 212 the coded energy supplied to the prima y 1 of track transformer TZ controls the train carried cab signal. With the deenergizing of relay I 2?, the coded energy supplied to the primary 21 of track transformer T will be delivered overthe circuit including front contact 100 of relay MP wire 101,

back contact 147, wire 148, back contact 149, wire 150, 40 code contact 28 of code transformer-CT and wire BXllQ to secondary 9 of GW, and from the other terminal of secondary 9 to primary 21 by wire CXllO a Thus with the train in the section W X, 40 code energy is supplied to thetrackcircuit of section VW which will cause relays 2H", 2DY and't2PV to become deenergized with the result that signal R is setat stop 'and in the event signal R, is an intermediate signal, 40 code energy is'supplied to the rails of the next section to the left and so on until each successive intermediate signal to, the next siding is set at stop. The 40 code energy will, in each case, retain the relay energized until the westbound train enters the section when it will become deenergized and train governing current dependent upon traflio conditions in advance will be supplied to the rails at the exit end of that section by means of the code feeding transformer T2 in a manner similar, to that just described for the section WX. As the train entered section WX, the deenergization of relay TP opened the circuit to the line relay MR3 at contact 151, and as the directional relay 28 remains deenergized, consequently, the relay MR receives noenergy and the result is that relays lD IH MP and IF? all become deenergized, and the signal L set in the relay' MP thewire BXllO is connected directlyto the primary 21 of the track transformer T through the back contact 152, and it follows then that the primary 21 is fed uncoded alternating current during the time the section W-X is occupied by a'westbound train; also, such would be the case for just an instant after a momentary short-circuit or an instant after 'a power failure; It follows that as the westbound train vacates section WV,-X,' uncoded alternating :cur: rent is fed to the section W,-X and the track relay TRW given an impulse to close its front contact. This impulse results in a change of flux in the decoding transformer 213T to induce onehalf cycle of alternating current inthe secondary of 2DT which will pick up relay TP and with relay 'I'P up, the- MR relay will. be operated with 80 code'current as follows: Secondary. GW, wireBXilO, 80 code contact 26 of CT"; front contact 153 of directionalrelay ls ,relay 18 having been picked up as the train entered the section VW, back contact 154, back contact 155,- frontrcon'tact 151,- line wire 18, relay MR line wire 17, and wire CX110 to the other terminal of secondary 9. This results in relay MR picking up to feed a code to the circuit of primary 21 of T continuing therefore, the energization of relay TP by the operation of the track relay TR? on code.

As the westbound train entered section VW, it shunted the trackrelay TR with the result that the TP relay drops to open the circuit to relay MR at the front contact 116. The relay MR being now deenergized, the associated relays lD IH MP and IP' are all deenergized. However, as IP" is slow-releasing, the directional relay lSW will be picked up as'stated above, by a'circuit which includes the front contact 66 of lP and the backcontact 64 of relay MP, and once directional relay IS up, and 80 code energy sup-.

plied to the relayMR as just described, it follows that the westbound signal L willassume a described for section WX' and likewise each successive sectionto the nextsiding. It will be observed that code energy is fed by the track transformer T to the rails of the track section to the rear of the westbound train; however, if a second westbound train follows this first train,

40 code current will be fed to the track circuit and the eastbound R signals set at stop.- It will also be noted thatif a'second westbound train enters the section W-X, while the first train occupies the section VW, 80 code energy is supplied to the rails of section WX by the code feeding transformer T2 in'place of the 180 code energy described in connection with the first train. This 80' code energy is supplied to the transformer TZ from the secondary 9 of transformer G over wire BXllO, 80 code contact of code transmitter CT front contact 111 of directional relay lS back contact 156, back contact 157, back contact 237, wire 236, primary 235 of T2", and wire CXllO to secondary 9, and this 80 code energy thus supplied to the section W-X will establish a caution cab signal for the second westbound train; Y a

To sum up the operation for a westbound train, we findthat 40 code energy is applied to the track oiall track sections to the next siding with the result that all eastbound signalsare. set to stop, that asa train enters a section, train governing code current is'applied to the rails at the exit end of the section to control train carried devices, that the westbound signals to the rear of the train are controlled by code energy applied to the master line relay, that the directional relays pro-'- vide protection'for following trains, and that the apparatus is responsive to trafflc conditions in advance of a train. 7

Such a system herein disclosed and described is practically immune from propulsion alternating current or direct current or any other form of electrical-energy that-may be used in the running rails. 'The coded line circuit reduces the possibility of inductive interference from commercial power lines to 'a remote possibility. I Such a system alsoreduces the first cost of that of present day systems in that it reduces to a minimum the number of line wires required. Furthermore,

such a system will operate equally as well for wayside signals alone or train carried cab signals alone or for both wayside signals and cab signals, v I I Although I have-herein shown and described only one form of railway trafllc controlling apparatusembodying my invention, it is understood that various changes and modifications may be made herein'within the scope of the appended claims without departing from the spirit and scope of my invention. 7

Having-thus described my invention, what I claim is:

1. A combined wayside and cab signal system for railways including a stretch of trackway ov r which traflic may move in either direction, a wayside signal located at each end of the stretch to govern trafiic through the stretch, means lo- 'cated at each end of the stretch to supply to the rails train governing coded current of different codes adapted to govern the operation of train carried cab signals, trackway means selectively responsive to the diiferent codes of the said coded current to govern the operation of said wayside signals, and directional means effective when'a train occupies the stretch traveling in either direction to selectively control the supply of coded current of different codes to the rails of the stretch at the end in advance of the train in accordance with traffic conditions ahead.

2. A combined wayside and cab signal system for railways including, a stretch of trackway over which traffic may move in either direction, a wayside signal located at each end of the stretch to govern traiiic through the stretch, means located at each end of the stretch to supply to the rails alternating current periodically interrupted at different rates adapted to govern the ope'ration'of train carried cab signals, trackway means selectively responsive to the different rates of the periodically interrupted alternating current to govern the operation of the said wayside signals, and directional means effective when a train occupies the stretch traveling in either direction to selectively control the supply of the said periodically interrupted alternating current to the rails of the stretch at the end' in advance ofthe train in accordance with traffic conditions ahead. i

I 3. A railway signal system including a stretch of trackway over which traffic, may move in either direction, a wayside signal located at each end of the stretch to govern traffic through the stretch, means located at each end of the stretch to supply to the rails coded alternating current of different codes, trackway means selectively responsive to the different codes supplied to the rails to govern the operation of the signals and to selectively control the supply of said coded current to the rails of the stretch in accordance with traffic conditions on either side of said stretch.

4. A railway signal system including a stretch of trackway over which trafllc may move in either direction, a source of alternating current, means associated with said source to normally supply alternating current to the rails adjacent one end of the stretch periodically interrupted at different rates; atrackrelay connected to the rails at the end opposite from said means responsive to alternating current periodically interrupted, decoding relays associated with the track relay, means to selectively energize said decoding relays in accordance with the rate of interruptions of the alternating current supplied to the track relay, traific controlled means to control said rate of interruptions in accordance with trafiic condi;

tions on either side of said stretch, and Wayside signals to govern traffic in opposite directions through the stretch controlled by said decoding relays. I

5. In a railway signal system including a stretch of single track railway arranged in track sections, a signal located at each end" of the stretch to govern trains traveling through the stretch, a source of train governingcoded current of different codes located at each end of each' track section to supply coded current to the rails adapted to govern train'carried devices on trains traveling in opposite directions through the stretch and arranged that at least one of the sources of each section is normally effective to supply coded current to the rails, a track relay for each section responsive to such coded current, a plurality of decoding relays associated with each track relay, means to selectively energize said decoding relays in accordance with the code with which the track relay is operated, and

directional means controlled by said decoding relays for governing the signalsand for selecting the code to be supplied to therails of each track section in accordance with the direction of movement of the train as it travels said stretch of single track.

6. In combination, a trackway arranged in track sections, a track circuit for each section, a line circuit for each section controlled by the track circuit, a line relay having a winding connected with the line circuit and responsive to periodic interruptions of alternating current in said line circuit, a plurality of decoding relays associated with said line circuit, means for selectively energizing said decoding relays in accordance with the rate of operation of the associated line relay, means controlled by the decoding relays of the line circuit for supplying alternating current to the line circuit of an adjacent track section pe-' riodically interrupted at different rates according to the conditions of the decoding relays, and signals controlled by the decoding relays.

'7. In combination, a trackway arranged in track sections, a track circuit for each track section,

I a line circuit for each section controlled by the track circuit, a line relay responsive to coded energy in said line circuit, a plurality of decod ing relays associated with said line circuit, means controlled by said line relay for selectively energizing said decoding relays in accordance with the coded energy supplied to the associated line circuit, means controlled by the decoding relays of the line circuit for supplying coded energy of different codes to the line circuit of an adjacent track section according to the conditions of the decoding relays, and signals controlled by the decoding relays.

8. In combination, a trackway arranged in track sections, a track circuit for each track section, a line circuit for'each section controlled by the track circuit, a line relay responsive to coded energy in said line circuit, a plurality of decoding relays associated with said line circuit, means controlled by the line relay for selectively energizing said decoding relays in accordance with the coded energy supplied to the associated line circuit, means controlled by the decoding relays of the line circuit for supplying coded energy of different codes to the line circuit of an adjacent track section according to the conditions oflthe decoding relays, and other means controlled by the deconditions of the section, a line relay for each.

section responsive to' coded energy in said line circuit, a decoding relay associated with each line relay and energized only when the line cir-' cuit is supplied with coded energy of a given code,

means to normally supply the line circuit with coded energy'of said given code, a signal for each section to govern traffic in one direction through the section controlled by the decoding relay and,

adapted to display aproceed signal when said decoding relay is energized, and a trafiic controlled means responsive to a train entering the stretch traveling ina direction opposite to that governed by the signal to cut ofi the normal supply of coded energy from the line circuit of each track section of the stretch.

10. In combination, a stretch of railway over which trafiic may move. in either direction arranged in a plurality of track sections, a line'cir cuit for each track section, responsive to trafiic conditions of the section, a line relay for each line circuit responsive to coded energy, a first anda second'decoding relay associated with each line relay respectively energized only when the line circuit is supplied with coded'energy of a first or a second code, a signal controlled byv said decoding relays to govern trailic through the section in one direction adapted todisplay a proceed signal when the first decoding relay is energized and to display an approach signal when the second decoding relay is energized, and traffic controlled means responsive to a train entering the stretch traveling in a direction opposite to that gov-l erned by the signal to prevent the line circuits of the plurality of track sections being supplied with coded energy of either said first code or said second code. i p

ll. In combination, a stretch of railway over which trailic may move in either direction arranged into a plurality of track sections, a line circuit for each track section, a line relay for each line circuit responsive to coded energy, coding means for each section to supply coded energy of a first code or of a second code to the line circuit and arranged to normally supply coded energy of the first code; a first and a second decoding relay associated with each line relay, with the first decoding relayenergized only when the line relay is operated by coded energy of the first code and the second decoding relay energized when the line relay is operated by either code; a signal for each section controlled by the first decoding relay, means controlled by the second decoding relay to control the line circuit for the track section to therear, and trafilc controlled means circuit responsive to coded energy, a decodingrelay associated with each line relay energized onlywlien-said line relay is operated by coded energy of a givencode, a signal for each track section controlled by the decoding relay adapted to display an approach signal when the decoding relay is energized, circuit means to supply the line circuit with coded energy of said given code out normally ineffective, and directional selective means to render said'circuit means of a given section effective to supply coded energy of the given code in response to a train entering'the track section next in'advance when traveling in the same direction, as that for which the signal governs. I v J 13. In combination, a stretch of railway over which traffic may move in either direction arranged in .track sections; a line circuit for each track section, a line relay connected to each line circuit responsive to coded energy, a decoding relay associated with each line relay and energized only whensaid line relay is operated by coded energy of a given code, a signal for each track section controlled by the decoding relay adapted to display an approach signal when the decoding relay is energized, circuit means to supply the line circuit with coded energy of said m given code but normally ineffective, a stick relay "when energized to render eifective said circuit means, and means to energize said stick relay in response to a train entering the track section next in advance when traveling in the same direction as that for which the signal governs;

14. In combination, a stretch of railway over which traffic may move in either direction arranged in track sections, a signal located at one end of each section to govern trafiic through the section in one direction, track circuit means con- "nected to the rails of each section at the end most remote from the signal to apply coded train governing energy to the rails, a line circuit for each section including a line relay responsive to coded energy, adecoding relay associated with "eachline circuit energized only when said line relay is operated by code energy of a given code to control the signal, coding means to supply said track circuit means and said line circuit with coded energy of said given code butv normally in- "effective, a stick relay when energized to render said coding means effective, and means to energize said stick relay in response to a train entering the track section next in advance when traveling in the same direction as that for which the signal governs; a

15. In combination, a stretch of single track railway arranged into a plurality of track sections, a line circuit for each track section, a line relay for each line circuit responsive to coded energ a decoding relay associated with each a signal for each section controlledby the deline circuit and energized only when said line relay is operated by coded energy of a given code, cod ing means to supply the line circuit with coded energy of said given code and normally eifective,

circuitfor each track section, a track relayv forv each track circuit responsive to coded energy, coding means for each track section to supply coded energy of either a first code or a second code to'the track circuit and arranged to normally supply coded energy of the first code; a first and a second decoding relay associated with each track relay with the first decoding relay energized only when the track relay is operated by coded energy of the first code and the second decoding relay energized when the track relay is operated by either code; traffic controlled means responsive to a train entering the stretch at a given end of the stretch to discontinue the supply of energy of the first code to the track circuit of all track sections of the stretch in advance of the section occupied by the train and to supply energy of the second code thereto, and signaling means controlled by the decoding relays.

17. In combination, a stretch of single track railway arranged into at least three track sections, a track circuit for each track section, a track relay for each track circuit responsive to coded energy, coding means for each track section to supply coded energy of either a first code or a second code to the track circuit and arranged to normally supply coded energy of the first code, a signal located at one end of the stretch to govern traflic in one direction through the stretch, traffic controlled means responsive to a train entering the stretch at the end opposite from the signal to discontinue the supply 'of coded energy of the first code to the track circuit of each track section of the stretch and to supply coded energy of the second code to the track circuit of all track sections other than that occupied by the train, and means to control the signal adapted to establish a proceed indication in response to ihe track relay of each track circuit being operated by the first code and to establish a stop indication in response to the track relays being operated by the second code.

18. In combination, a stretch of single track railway arranged into at least three track secions, 2. track relay for, each track section responsive to coded energy, coding means for each track section tosupply coded energy of either a first code or a second code to the track relay and arranged to normally supply coded energy of the first code, a signal for each track section to govern traffic in one direction through the section, traflic controlled means responsive to a train entering the stretch traveling in a direction opposite to that governed by the signals to discontinue th supply of coded energy of the first code to the track relay of each track section of the stretch and to supply coded energy of the second code to the track relay of all track sections other than that occupied by the train, and means for each section to control the signal of that section controlled by the track relay and adapted to establish a proceed indication in response to the track relay being operated by the first code and to establish a stop indication in response to the track relay being operated by the second code.

l9. In a railway signal system, a stretch of railway over which trafiic may move in either direction arranged in track sections, a master line relay and a track relay for each track section each responsive to coded energy, means for each track section to normally supply coded energy of a given codeto both of said'relays, a trafiic directional means to continue the supply of coded to attrain entering. the stretch atitheaopposite end; and two signals forthe.stretch oneosignal io -igovern iraflic .in 1 one direction through the stretchandlhelduinia clear .positionwhen the Z 5 filine 'r'elay-sof 1 each .section is: operated .by coded :energy :of'i the I given code,. and :the other signal to. govern ttraific -in'the opposite ;direction and meldinaazclear: position when the track relay o1 :eachisectioni isitoperated'byooded energy of the 1 xgivenz code.

.2 O.. ."In arrailwayr signal system; a stretch of 1 railway nover'whichvtraific may move in either idirectionxarranged in .track sections, a track cir- :ycuitz and:.a';1ine' circuit for each track section, means forzeach: track section to normally supply coded? energy .of .acgiven code to .the track circuit .LfllldItO'lthEffli-Dfii circuit of I the section, a traffic zzdirectionalimeans tocontinue the supply of coded I ienergyiof saidgivencode to the track circuit only lot each track: section in response to a train enter- -inga thesstret'ch atxone :end and to continue the :supply:ofwsaidwgiven; codeto. the line circuit only of each track section in response to-a train enter- .ringtthestretchzatthe opposite end; and two sig- 63251;:nals: fon the: stretch, F0116 signalto govern traino sin'onepdirection through the stretch and held in azclcarpositionawhen the line circuit of each sec- 'ztiomis; supplied with coded energy of the given rcodeandstheothersignal to; govern traflic in the lfioooppositetdirection through the stretch andheld uirsa:clcanpositiomwhen thetrack circuit of each streak" section'vis' supplied with .the' given code.

21.. In arailway sign lsystem,.a stretch of railnwayzoverwhich traflic: may movein either :directionxxarrangedxin track sections, [a track [circuit caandza line. circuit foreach track;section,.a track Y A relayfor'caohtrack circuit and amaster line relay .for reach-:line. circuit, each of said -relays being s-responsive tocoded.-energy,:-means foreach track uo section to normally supply coded energy of a iwgivenicode to thetrack circuitzand'to-the line. circuit :of the sectiom-a: traffic directional. means .to I

aycontinue.:thesupplyof codedenergyof said given code to-itheltrack circuitonlyof eachtracksec- 1:15 -,tion in response toa train entering .the stretch at aoneend'iand to continue the supply of saidgiven oodeitothe-tline. circuit only ofeachtrack section response'toa train entering the stretchat the wzopposite-endpand-two signals for thestretch, one .;;50. signal togovern trafiic in one direction through thestretch and held in-aclear, position when. the aline-orelay of. theline. circuit of eachsection is coperated by. codedenergy'of thegiven 'code, and wtheother-signalto govern-.trafilc inithe opposite ggmdirection through; the stretch and .held inoa clear epositionwhen the track relay. ofsthe track circuit -.of-each-section is operated by the. givencode.

22 In a; railway signal system, a stretchof railway over which traific may move in either direo fiookt-ion'z'arranged in-ttrack-sections, a track circuit A'Hl'ldirE'FliIlG .circuit for eachsection; a track *relay' for eahlritraclr:circuit and arma'sterline relay for each line circuit each of said relays being-respon-' accordingrto the conditions of'the said-first set.

of decoding'relays, and a second-set of decoding -relays -associated witheach master line relay-selectively energized inaccordance with the coded said first set of decoding relays, and a second .set of decoding relays associated with each'master section to supply coded energy of-different'codes to the track circuit and to the line circuit of the section, a signal at each end. of a section torgovern traffic throughthe-section, a-first setxofadecoding'relays associated with each track relayse- 1 lectivelyenergized in accordance withthecoded energy supplied to the track circuit to control one signal and the track circuit for the. track section to the rear according to the 'conditions;.of-,:the

line relay. selectively energized in.. accordance .with the coded'energy supplied to. the line circuit to control the other signal and the linecircuit for the track section to the rear according to the conp ditions of the said second set of decoding. relays. 24. In combination, a track section :through which trafiic may move in GithGI'zdlIGCtiODH8 first signal located at one end of the traek section to govern trafiic in one direction. through the section, a first receiving and'decoding means =means selectively responsive tocoded-energy of different codes to control said second signal,=,and trafiic controlled means to supply .in accordance with traffic conditions, coded energy of different;

codes to said first and second receiving and decoding means.

Jtrack section to supply to. the rails coded-train governing current to control traflic in one directionxthrough the section, a first receiving and .the other end of thetracksection to supply to .the rails coded train governingcurrent to control trafficin the other .direction.'through.,.the sectiQn a second receiving and decoding 111881183130 selectively responsiveto coded current of different codes to control said second circuit means,

and traffic controlled means to supply iriaccord- "ance with traffic conditions coded 'current'of different codes to said first and second-receiving and decoding means.

26. In combination, a track section over which traflio may move: in either direction, ausource of current located at each end ofvthe section,

coding means associated with eachsourceadapt tlcn ed to' supply train "governing .codedwcurrent-aof different codes to the. rails ofithe section-and arranged that one of said codingxmeans is nor- ..mally effective to supply current to therailsand the other of said codingmeans normally .ineflectivega track relay connected toxtherailst'otthe section responsive'tocoded current; atplurality of decoding relays, meansv associated withzzthe :track. relay to selectivelyenergize said decoding relays. inv :accordance .-:with;the code.- supplied:.t fi

the track relay, and circuit. means controlled by the decoding relays to control the supply of train governing coded current to the rails of the track sectionon either side of said track section inaccordance with traffic conditions.

' 27-. In combination, a track section over which 'traflic may move in either direction, a signal "located at each end of the track section to govern traflic through the section, 'a source of current located at each end of the section, coding means associated with each source adapted to supply relay connected to the rails of the section responsive to coded current, a plurality of decoding relays, means associated with the track relay toselectively energize said decoding relays in accordance with the code supplied to the track "relay, a first circuit means controlled by said decoding relays to control the operation of the said signals, and a second circuit means controlled by. the decoding relays to control the v supply of train governing coded current to the rails of the track section on either side of said --track' section in accordance with trafiic conditions. g

-28. In combination, a track section over which trafiic may 'move in either 'direction', a signal located at eachend of the track sectionto govern traflic through the section, a source of current located at each end'of the section, coding means associated with each source adapted to supply train governing coded current-oi different codes -to' the rails or the section and arranged that one of said coding means is normally efiective to supply current and the other of said coding 'meansnormally ineffective, a track relay connected to the railsof the section responsive to coded current, a plurality of decoding relays, 'means associated with the track relay to'selec-' tivelye'nergize said decoding relays in accordance with the code supplied to the track relay,

a first circuit means controlled by said decoding relays to control the operation of the said signals,'and a second circuit means controlled by the decoding relays to control the supply ot'train' governing coded current to the rails of the section l'n'accordance with trafiic conditions.

29. In combination, a track section over which tratlic may move in either direction, a signal located at one end of the track section to govern trafllc' in one direction through the section, a second signal locatedat the other end of the section to govern .trafiic in the other direction through the section, a source of .current located at each end of the section, coding means associated with each source tosupply train governingcoded current'tothe rails of the section and arranged thatone of said coding meansis normally effective to supply. current and the other of said coding means normally ineffective, a'track relay connected to the .rails' of the section at ;the end opposite from the normally effective coding means and said relay responsive to coded -.current, a .decodingrrelay; means associated with the track relay to energize said decoding'relay when said track relay is operated by coded cur- :signals, and a second circuit means controlled .rent,-a first circuit means-controlled by said decoding relay to control the operation of said train governing coded current to the rails by each of saidcoding means. i I

30. A railway signal system including, a stretc of traffic rails arranged in track sections, a track circuit for each section having a source of coded -f- 30 current connected across the traflic rails at one end of the section and a code followingtrack relay connected across'the rails at-the opposite end of the section normally operated by the coded current, a decoding device, means to energize said decoding device in response to the track relay operated by coded current, and means controlled by the decoding device to supply coded current to the traific rails of the adjacent track section on each side of said track section. l

i 31. In combination, a section of a railway track, a-device for governing traffic movements in 'said section, a track circuit for said'.section,.means controlled by a train adjacent said section in a first and a second direction from said section for controlling said track circuit, and means controlled by said track circuit for controlling said trailic governing device. i 32. In combination, a section of railway'track, a device for governing trafiic movements in said section, a transformer connected across the rails of said section, means controlled by'a train entering said section from a given direction for causing said transformer to supply periodically varied alternating current to the rails of said 105 section in advance of said train,*means controlled by a second train entering said section froma second direction for causing said transformer to supply-constant" alternating current to the rails of said section in the rear of said second train,a 1'10 relay connected across the-rails of said section 'andresponsive to said periodically varied'and 1 said constant alterating currents, and means concording to a first or a'se'cond'code, means controlled by said track circuit for selectively con-T trolling traffic movements in one direction in said section in a first or a second manner responsive to the first and second codes respectively 'of said track circuit, and means controlledby said coded line circuit for selectively controlling trafiic movements in a second direction in said section, in a first or a second manner responsive to the first and second codes respectively of said line circuiti 1 i 34. In combination, a stretch of railway track divided into a plurality of sections, a track circuit for each of said sections including the track rails periodically varied at a first or 'a second code, a line circuit for each of said sections periodically varied at a first or ;a second code, means controlled bysaid track circuits for selectively, controlling traflic movements in a given direction in said stretch inga-first or a. second manner responsive to the first and second codes respectivelyof said track circuits, and means controlled by said linecircuits for selectively controlling traific movements in the oppositedirection in said stretch in a first or a second manner responsive to the first and second codes respectively of said line circuits. 1

35. In combinatiorna section of railway track, a device supplying coded current to a given end of said section for controlling train carried apparatus for governing traffic movements in a,

first direction in said section, wayside apparatus controlled by said coded current for governing trafiic movements in said first direction and in a second direction in said section, and a second device supplying a second coded current to a second vend of said section for controlling train carried apparatus for governing, traflic movements in said second direction in said section.

36. In combination, a section of railway track, a transformer connected across the rails adjacent a given end of said section for supplying current to said rails, an impedance transformer, a relay connected in series with the secondary winding of said impedance transformer across the rails adjacent a second end of said section,'

short-circuiting the primary winding of said impcdance transformer to permit operation of said relay by current from said first transformer, and means controlled by said relay and by current supplied to said section by said code feeding transformer for governing trafiic movements in said section.

' RALPH R. KEMMERER, 

